When Should We Doubt Expert Consensus? Part 2

8. When the subject matter seems, by its nature, to resist consensus. An an engineer, this point has always bothered me about both evolution and climate change. Richards explains:

It makes sense that chemists over time may come to unanimous conclusions about the results of some chemical reaction, since they can replicate the results over and over in their own labs. They can see the connection between the conditions and its effects. It’s easily testable. But many of the things under consideration in climate science are not like that. The evidence is scattered and hard to keep track of; it’s often indirect, embedded in history and requiring all sorts of assumptions. You can’t rerun past climate to test it, as you can with chemistry experiments. And the headline-grabbing conclusions of climate scientists are based on complex computer models that climate scientists themselves concede do not accurately model the underlying reality, and receive their input, not from the data, but from the scientists interpreting the data. This isn’t the sort of scientific endeavor on which a wide, well-established consensus is easily rendered. In fact, if there really were a consensus on all the various claims surrounding climate science, that would be really suspicious. A fortiori, the claim of consensus is a bit suspicious as well.

9. When “scientists say” or “science says” is a common locution. Which scientists? The ones that agree with the theory? Since when does science speak for itself without human beings interpreting?

10. When it is being used to justify dramatic political or economic policies. Always be suspicious when politicians and ideological activists are wielding the sword of science to further a particular agenda. As Richards notes, that is happening in spades in the global warming debate.

11. When the “consensus” is maintained by an army of water-carrying journalists who defend it with uncritical and partisan zeal, and seem intent on helping certain scientists with their messaging rather than reporting on the field as objectively as possible. In the last few years, I can recall weeks where our local newspaper was running story after story about global warming, and none of them critical of it. When the supposedly unbiased media line up and promote one viewpoint with little dissent, be suspicious.

12. When we keep being told that there’s a scientific consensus. Richards captures the essence of this point:

A scientific consensus should be based on scientific evidence. But a consensus is not itself the evidence. And with really well-established scientific theories, you never hear about consensus. No one talks about the consensus that the planets orbit the sun, that the hydrogen molecule is lighter than the oxygen molecule, that salt is sodium chloride, that light travels about 186,000 miles per second in a vacuum, that bacteria sometimes cause illness, or that blood carries oxygen to our organs. The very fact that we hear so much about a consensus on catastrophic, human-induced climate change is perhaps enough by itself to justify suspicion.

Some food for thought. I think Richards has done a wonderful job putting into words some of the intuitions we have about science and its reported results. In fact, most of his 12 points apply to other non-scientific fields where we’re told there is a consensus. There is nothing wrong with consensus, inherently, but we just need to be vigilant and do our homework before concurring with an alleged “consensus.”

How do I determine what a subject matter’s “nature” is? And what particular characteristic of its “nature” makes it resistant to consensus? And who is doing the observation with the term “seems”?

Bill Pratt

Some things are easily observable and repeatable. We can test these hypotheses over and over and see the results right in front of our eyes. Other things are not directly observable and not easy to demonstrate. Climate change theories are projecting into the future what will happen to weather patterns. They do this by using complex models that make tons of assumptions. Surely you can see how these model results, as projections of the future, are less sure than the claim that apples fall to the ground when you drop them from a height.

There is a continuum of certainty (from totally uncertain to totally certain) when it comes to scientific results, but many people think that all scientific claims are equally certain. Richards is just pointing this out.

Ah…Then would you agree Jesus’ resurrection is a subject matter that seems, by its nature, to resist consensus, as it…too…is not easily observable or repeatable or testable? And therefore we likewiseare justified in doubting any consensus of experts, like Dr. Habermas’ claims regarding his minimal facts?

Bill Pratt

I would agree that assessing the historicity of events of ancient history is more difficult and less certain than assessing whether apples fall to the ground. Any time we deal with history, we are dealing in probabilities, as you’ve said many times before. But remember, as Richards points out, sometimes the consensus is right.